Macro- and Micro-characteristics of Clouds and Precipitation During the 7·20 Extreme Rainstorm in Zhengzhou, China

To simulate and analyze the main features and differences in rainfall and cloud macro- and micro-physical properties during an extreme rainstorm in Zhengzhou, Henan, China, that occurred on July 20, 2021, three cloud microphysics schemes—weather research and forecasting single-moment 6-class microphysics (WSM6), Thompson, and LiuMa—were applied using the China Meteorological Administration mesoscale (CMA–MESO) model. Simulations based on all three schemes successfully reproduced the 24-hour accumulated rainfall. Among them, the maximum 24-hour accumulated rainfall simulated by the WSM6 scheme was the closest to observation values. However, challenges remain in simulating the temporal evolution of precipitation intensity, particularly that of maximum hourly rainfall. The maximum hourly precipitation simulated by the LiuMa scheme was the closest to the observations in terms of spatial distribution, intensity, and radar echoes. Cold and warm cloud precipitation processes jointly dominated the entire event; however, warm cloud precipitation dominated during the period with the maximum hourly precipitation. The vertical distributions of liquid-phase hydrometeors simulated by the three schemes were relatively consistent, whereas the simulations of ice-phase hydrometeors were sensitive to the specific scheme used. During the period with the observed maximum precipitation intensity, the vertical distributions of raindrop size and terminal velocity, as modeled by the three schemes, were well-aligned.